From 105d02993b86eea2e31b076b5161837e2f6171a2 Mon Sep 17 00:00:00 2001
From: Bulat-Ziganshin <bulat.ziganshin@gmail.com>
Date: Fri, 26 Aug 2022 04:21:23 +0300
Subject: [PATCH] Used copyAllScalarFields when building unprotected Manifest
 from a protected one

---
 codex/erasure/erasure.nim   |  9 ++++-----
 codex/manifest/manifest.nim | 35 +++++++++++++++++++++++++++--------
 2 files changed, 31 insertions(+), 13 deletions(-)

diff --git a/codex/erasure/erasure.nim b/codex/erasure/erasure.nim
index e1252b43..317d2ff2 100644
--- a/codex/erasure/erasure.nim
+++ b/codex/erasure/erasure.nim
@@ -156,8 +156,7 @@ proc encode*(
 proc decode*(
   self: Erasure,
   encoded: Manifest): Future[?!Manifest] {.async.} =
-  ## Decode a protected manifest into it's original
-  ## manifest
+  ## Decode a protected manifest into its original manifest
   ##
   ## `encoded` - the encoded (protected) manifest to
   ##             be recovered
@@ -254,10 +253,10 @@ proc decode*(
   finally:
     decoder.release()
 
-  without decoded =? Manifest.new(blocks = encoded.blocks[0..<encoded.originalLen]), error:
-    return error.failure
+  without decoded =? encoded.unprotect(blocks = encoded.blocks[0..<encoded.originalLen]), error:
+    return failure error
 
-  return decoded.success
+  return success decoded
 
 proc start*(self: Erasure) {.async.} =
   return
diff --git a/codex/manifest/manifest.nim b/codex/manifest/manifest.nim
index 1d90f879..53fb86c6 100644
--- a/codex/manifest/manifest.nim
+++ b/codex/manifest/manifest.nim
@@ -153,7 +153,10 @@ proc cid*(self: Manifest): ?!Cid =
 # Constructors
 ############################################################
 
-func copyAllScalarFields(original: Manifest): Manifest =
+func copyAllScalarFields(
+  original: Manifest,
+  protected: bool
+  ): Manifest =
   # Sometimes we need to copy all but a few fields
   # from a manifest to another one.
   # It can be mplemented by copying all fields and then
@@ -169,9 +172,9 @@ func copyAllScalarFields(original: Manifest): Manifest =
     version: original.version,
     hcodec: original.hcodec,
     codec: original.codec,
-    protected: original.protected)
+    protected: protected)
 
-  if original.protected:
+  if copy.protected and original.protected:
     copy.K = original.K
     copy.M = original.M
     copy.originalCid = original.originalCid
@@ -187,7 +190,7 @@ proc new*(
   hcodec = multiCodec("sha2-256"),
   codec = multiCodec("raw"),
   blockSize = BlockSize): ?!T =
-  ## Create a manifest using array of `Cid`s
+  ## Create a dataset from an array of `Cid`s
   ##
 
   if hcodec notin EmptyDigests[version]:
@@ -205,16 +208,14 @@ proc new*(
   T: type Manifest,
   manifest: Manifest,
   K, M: int): ?!Manifest =
-  ## Create an erasure protected dataset from an
-  ## un-protected one
+  ## Create an erasure protected dataset from an unprotected one
   ##
 
   ? manifest.verify()
   if manifest.protected:
     return failure newException(CodexError, "Trying to protect already protected manifest")
 
-  var self = copyAllScalarFields(manifest)
-  self.protected = true
+  var self = copyAllScalarFields(manifest, protected = true)
   self.K = K
   self.M = M
   self.originalCid = ? manifest.cid
@@ -237,6 +238,24 @@ proc new*(
   ? self.verify()
   self.success
 
+proc unprotect*(
+  manifest: Manifest,
+  blocks: openArray[Cid] = []
+  ): ?!Manifest =
+  ## Create an unprotected dataset from an erasure protected one
+  ##
+
+  ? manifest.verify()
+  if not manifest.protected:
+    return failure newException(CodexError, "Trying to unprotect already non-protected manifest")
+
+  var self = copyAllScalarFields(manifest, protected = false)
+  self.blocks = @blocks
+
+  ? self.verify()
+  self.success
+
+
 proc new*(
   T: type Manifest,
   data: openArray[byte],